According to the report of Japan Economic News Network on May 19, this currency was minted in China from 14 to 40, and spread to Japan in the yayoi period (about 300 BC to 250 AD).
According to the report, the South Awaji Island Municipal Education Commission said that including this time, a total of 179 "cargo springs" were found in Japan, but it is extremely rare to find several coins in an overlapping state like this.
The person in charge of the Awaji Island Education Committee said, "The transmission of ancient currency in China has become an important historical material to prove that Awaji Island was an important maritime trade hub in the late yayoi period".
Introduction of ancient copper coins in the Ring of Fire;
Fire ring is the most common coin in Han Dynasty, and it is the product of the fourth currency reform in the first year of Wangmang Tianfeng (AD 14). From the first year of Tianfeng, Emperor Guangwu of the Eastern Han Dynasty, to the sixteenth year of Jianwu (AD 40), Pinquan was basically a common variety, among which the versions were double profile, half star, left fixed and right fixed. And most of the standard coins are marked with the casting place. The technology and quality of the general double profile format are better, which may be invested by the central government in the early stage. The inscriptions dotted around should be cast by money stoves in other places. The casting is not very accurate, it may be late.
Generally speaking, the size and weight of the early futures spring are not much different, the technology is better and the standardization is higher; However, from the late New Dynasty to the early Eastern Han Dynasty, due to the continuous social unrest and the struggle between various rebel forces and powerful armed forces, the economy was greatly damaged, and a large number of small bad coins and privately minted goods springs appeared. The weight of the spring I have seen in the late private casting is less than half of normal.